Landslides triggered by the 10 June 2022 Maerkang earthquake swarm, Sichuan, China: spatial distribution and tectonic significance

On June 10, 2022, an earthquake swarm including three major earthquakes with magnitudes of Ms5.8, Ms6.0, and Ms5.2 occurred in Maerkang, Sichuan, China. According to statistics, at least 650 landslides have been triggered by this earthquake, with a total area of 1.2 km(2). In this study, the spatial distribution of these landslides and their correlation with seismic, topographic, and geological factors were analyzed based on the coseismic landslide inventory. The results show that landslides are mainly distributed on the northeast side of the Songgang-Fubianhe fault (SG-FBHF), which is a VII intensity area. The closer to the epicenter, the more concentrated the landslide distribution. The landslide density increases significantly with increasing slope. The strata of the Upper Triassic Zhuwo Formation are more prone to coseismic landslide occurrence. Our results, when combined with the focal mechanism solution, precise location of aftershocks, and geological characteristics of the SG-FBHF, suggest that this earthquake is a left-lateral strike-slip earthquake along the SG-FBHF, and the seismogenic fault is slightly tilted to the northeast. In addition, nearly 70% of coseismic landslides are concentrated in the extreme seismic area of similar to 225km(2), indicating that the seismic energy release is highly concentrated. This work analyzed the distribution of landslides triggered by a moderately strong earthquake swarm, providing a typical case for researchers to understand the spatial distribution pattern of earthquake-triggered landslides and a scientific support for disaster prevention of coseismic landslides in southwestern Sichuan, China.